(a) Field of Invention
The present invention relates to a straightness management system and a control method thereof, and more particularly to a straightness management system of a mounting pin inserted in an aperture for assembly and a control method of the system.
(b) Description of Related Art
In a vehicle body assembly line, generally a front subframe forms a support structure of a front vehicle body by being fixed to a lower side of a left/right front side member in the front of a vehicle body. In addition, in an essential front chassis process among assembly lines of a passenger vehicle, an engine and a transmission are mounted on and supported by the front subframe. In addition, referring to FIG. 3, a front chassis suspension module 4 is connected and mounted to the left/right front side member, which module simultaneously sustains a front vehicle body and reduces impacts or vibrations transferred to the vehicle body through contact of road surface and tires.
In FIG. 3, assembling portions and methods of a front vehicle body structure 3 comprising a left/right front side member and a mounting pin 1 fixedly mounted to both sides of a lower side of the left/right front side member and the suspension module 4 are shown. In particular, a 3-dimensional coordinate system of T/L/H is used where T stands for a length direction of a vehicle body, L a width direction, and H height direction. As shown in FIG. 3, the mounting pin 1 is used for assembly in the H direction of a vehicle body and chassis parts. Further, a degree of precision for mounting pin 1 has an effect on mounting variance of the suspension module 4 and is directly related to a problem of vehicle tilting during driving. Therefore, quality control is required, but development of a system to measure a mounting pin in assembly lines or a variance management algorithm has not been developed. While precision management of a mounting pin unit is conducted, a degree of precision for mounting pin mounted to a vehicle body before painting, namely, Body in White (BIW) is not managed in an assembly line. Accordingly, the assembly line may unexpectedly stop or a safety accident of a completed vehicle may occur during driving.
The information disclosed in this section is merely for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.